1. Field of Invention
The invention concerns a process for laser beam welding with reduced formation of end craters, according to the precharacterizing portion of Patent Claims 1 and 3. Processes of this general type are already known from DE 196 30 521 A1.
During laser beam welding a so-called end crater forms at the end of the weld seam. The end crater is formed by the volume shrinkage of the solidifying melt after the laser beam reaches the seam end and is switched off or repositioned. The end crater acts as a geometric notch or groove and decreases the mechanical properties, and in particular the operational stability of the weld seam, so that holes or tears in the area of the end crater can occur.
2. Related Art of the Invention
For reducing the formation of end craters, it is taught in DE 196 30 521 A1 to reduce the laser output at the seam end (so-called “power ramp”) or to increase the weld speed (so-called “speed ramp”).
This procedure reduces the problem slightly, but is however frequently insufficient.